This invention relates generally to ultranocrystalline diamond (UNCD) structures and is more particularly directed to UNCD structures for use in sensors and other devices with special application for highly sensitive, ultra-small devices such as used in micro electro mechanical systems.
Micro electro mechanical systems (MEMS) cantilever sensors are used as detectors in shock and acceleration sensors. One common application of a MEMS detector is in the activation of air bags in vehicles. The MEMS detector is typically made of silicon because of the availability of surface micromachining technology. However, these devices have limited dynamic range because of the limited flexural strength of silicon. If the cantilever deflection exceeds the elastic limit of silicon, the cantilever structure breaks. Moreover, the tribological properties of silicon are such that it has a tendency to adhere to surfaces with which the cantilever beam comes into contact. In addition, the silicon is subject to high friction and wear in applications involving sliding and rolling contact. Because of these characteristics of silicon these cantilever structures are normally limited to simple on-off switches such as in the aforementioned vehicular air bag application, rather than having application to a broad range of measurement devices.
The present invention addresses the aforementioned limitations of the prior art by providing a miniature, highly sensitive ultrananocrystalline diamond structure for use in a sensor having a wide dynamic range which is adapted for use in a wide range of applications.
Accordingly, it is an object of the present invention to provide an ultrananocrystalline diamond (UNCD) structure for use in sensors and other devices such as in micro electro mechanical systems (MEMS).
It is another object of the present invention to provide an ultra-small sensor, and a method of fabrication therefor, for precisely measuring acceleration shock, vibration and static pressure over a wide dynamic range.
A further object of the present invention is to provide a highly sensitive, miniature sensor and associated circuitry which is particularly adapted for use in atomic force microscopy.
Yet another object of the present invention is to provide a sensor having a wide dynamic range which can be used in a wide variety of applications such as in, for example, explosive shock sensors, pressure/vibration transducers for aircraft and space vehicles, acceleration sensors/feedback devices for air and ground vehicles, and data-logging applications.
A still further object of the present invention is to provide a sensor capable of the simultaneous detection of and discrimination between vibration and acceleration.
The present invention contemplates a sensor for measuring an acceleration, vibration or pressure, the sensor comprising a substrate having a general flat surface; an ultrananocrystalline diamond (UNCD) element having first and second opposed ends, wherein said UNCD element undergoes deflection from an equilibrium position in response to acceleration, vibration or pressure; a mounting member disposed between and coupled to the substrate and the first end of the UNCD element for attaching the UNCD element to the substrate in a cantilever manner, wherein the second opposed end of the UNCD element is deflected from the equilibrium position toward or away from the substrate in response to an acceleration, vibration or pressure; and a detector coupled to the UNCD element for measuring deflection of the UNCD element from the equilibrium position, wherein the deflection represents an acceleration, vibration or pressure experienced by the UNCD element.